| Reproducibility of color Doppler imaging. | |
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MedLine Citation:
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PMID: 19760224 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: The aims of this study were: (1) to determine the intra-subject and inter-observer variability of color Doppler imaging (CDI) measurements and readings of the retrobulbar blood vessels, (2) to compare the difference invariability of CDI parameters in non-glaucomatous controls versus glaucoma patients, and (3) to provide calculations of minimum sample sizes for future CDI studies. METHODS: Patients with normal tension glaucoma (n=28), primary open-angle glaucoma (n=19) and non-glaucomatous controls of comparable age (n=22) underwent CDI on two occasions 1 month apart. Variability in CDI parameters was quantified using (within-subject) coefficients of variation. Based on this variability, minimum sample sizes were calculated to guide the design of future studies comparing CDI between and within groups. RESULTS: In general, within-subject coefficients of variation for measurements 1 month apart were comparable to previously reported short-term variations. Variability was higher in glaucoma patients than in non-glaucomatous controls. The minimum sample size required for glaucomatous study populations is larger than for non-glaucomatous controls. Smaller patient groups are required to detect change using the peak systolic blood flow velocities than using end diastolic velocities. Studies using a cross-over design require smaller sample sizes than studies with a prepost or particularly parallel design. CONCLUSIONS: This study provides extensive information on long-term intra-subject variability of CDI measurements in non-glaucomatous controls as well as glaucoma patients. Moreover, sample size calculations are provided for studies involving glaucoma patients as well as non-glaucomatous individuals, using three different commonly used study designs. |
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Authors:
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Ingeborg Stalmans; Brent Siesky; Thierry Zeyen; Steffen Fieuws; Alon Harris |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv für klinische und experimentelle Ophthalmologie Volume: 247 ISSN: 1435-702X ISO Abbreviation: Graefes Arch. Clin. Exp. Ophthalmol. Publication Date: 2009 Nov |
Date Detail:
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Created Date: 2009-10-08 Completed Date: 2009-11-04 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8205248 Medline TA: Graefes Arch Clin Exp Ophthalmol Country: Germany |
Other Details:
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Languages: eng Pagination: 1531-8 Citation Subset: IM |
Affiliation:
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Department of Ophthalmology, University Hospitals Leuven, Campus St Raphaël, Leuven, Belgium. ingeborg.stalmans@uzleuven.be |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Aged Aged, 80 and over Blood Flow Velocity Blood Pressure Ciliary Arteries / physiology* Glaucoma, Open-Angle / physiopathology* Humans Intraocular Pressure Middle Aged Observer Variation Ophthalmic Artery / physiology* Regional Blood Flow Reproducibility of Results Retinal Artery / physiology* Tonometry, Ocular Ultrasonography, Doppler, Color* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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